The present invention relates to an electromechanical horn warning system.
More particularly, the present invention relates to an electromechanical horn warning system especially suitable to be applied on motor-vehicles.
Electromechanical horn warning systems are known that comprise a hollow body open at an end, an electric bobbin housed within the hollow body, and a membrane having a movable core fixed at the edge of the open end of the hollow body.
The electric bobbin is fixed to the wall of the closed end of the hollow body and is in communication with a contact breaker. The contact breaker includes a support, a spring provided with electric contacts and an insulating plate sandwiched between the support and the spring. As is known, the electromechanical horn warning systems of this type produce undesired electromagnetic transients during operation.
To prevent this drawback, a resistor of adequate value is connected parallel to the contact breaker by fixing one end to the support and the other end to the spring of the contact breaker. The resistor operates to attenuate electromagnetic transients by causing a drastic drop of the overvoltages produced by the opening and closing of the electric contacts.
Although the resistor provides adequate transient suppression, its introduction imposes drawbacks of both a constructive and a functional character.
A first drawback is that the resistor constitutes a constructive complication in that it requires electrical connections and special supports which increases the manufacturing cost of the horn warning system.
A second drawback is that the resistor can be damaged and/or the electrical connections may break due to vibration and/or temperature changes that derive from running the vehicle and/or operating the horn warning system. This leads to system malfunction.
The object of the present invention is to obviate the above drawbacks. More particularly, object of the present invention is to provide an electromechanical horn warning system that includes electromagnetic transient suppression and obviates the drawbacks of a constructive and functional character referred to hereinabove.
The present invention provides an electromechanical horn warning system that includes a hollow body having a wall of a first cylindrical part closed by a bottom wall, a second flat part, a third cylindrical part and a flanged edge. At least one bobbin abuts on the bottom wall of the first cylindrical part. An elastic membrane, provided with at least one movable core is fixed to the flanged edge of the hollow body.
At least one contact breaker is provided having a support, a spring provided with electric contacts, and an insulating plate sandwiched between the support and the spring. The insulating plate is provided with at least one layer of resistive silk-screen ink that has a global resistance suitable to eliminate electromagnetic transients.
The at least one layer of resistive silk-screen ink may be coated on one, and preferably both, of the surfaces of the insulating plate.